Unroasted coffee beans may help people lose weight, according to research presented Tuesday at the annual conference of the American Chemical Society. The study involved only 16 patients, but the results showed a strong link between using the supplement and weight loss.

Applied Food Sciences, a maker of green coffee extract, funded the study conducted in India that has not undergone peer-review publication.

Study volunteers maintained their usual diet and doctors tracked body weight over a six-month period. Participants took capsules daily with 700 milligrams or 1,050 milligrams of unroasted green coffee extract or a placebo.

On average, participants taking green coffee extract daily lost 17 pounds over the course of the study - a nearly 11 percent decrease in body weight, researchers said.  

This was indeed a small study, Joe Vinson, study coauthor and professor of chemistry at the University of Scranton, told HealthDay. But here, with higher extract doses than have been used before, the patients experienced what I would call rather large weight loss.

Prior studies conducted in France and Japan saw mild weight loss with lesser doses of green coffee extract.

Although green coffee extract could have benefits, it is premature to recommend this approach, Dr. David Katz, director of Yale University's Prevention Research Center, told ABC News.

It's a supplement, not a substitute, he said. The emphasis will always need to be on overall diet and physical activity.

Researchers did not focus on the weight loss impact of caffeine, but instead on chlorogenic acid, a compound found in unroasted coffee that the roasting process destroys .

[Chlorogenic acid is] the main natural compound in unroasted coffee, and roasted coffee has much, much less of it than unprocessed coffee, Vinson told HealthDay. So we're not talking about something that is interchangeable with the coffee we drink.

Some researchers say focusing on caffeine's role in weight loss would have improved the study.

I'd be happier if the research included pure caffeine, in the same amount as is contained in the two doses of [green coffee bean extract], Keith Ayoob, a registered dietitian and associate professor at the Albert Einstein College of Medicine in New York, told ABC News . Then you'd know if the effects are due solely to caffeine or to something else in the beans, or to some combination thereof.